Modified bisphenol resins having at least one arylcyclo-butanenealkyl moiety

ABSTRACT

Rigid, relatively insoluble resins of the thermoset type are produced by heating ring-arylcyclobutenealkylated di(hydroxyphenyl) compounds having at least one arylcyclobutenealkyl moiety attached to at least one of the phenyl rings.

RELATED APPLICATIONS

This application is a continuation-in-part of copending application Ser.No. 349,544 filed May 9, 1989 now U.S. Pat. No. 4,609,956 (10-2-90).

1. Field of the Invention

This invention relates to cured products derived from certainring-alkylated derivatives of di(hydroxyphenyl) compounds. Moreparticularly, the invention relates to cured products obtained byheating di(hydroxyphenyl) compounds having at least onearylcyclobutenealkyl moiety attached to at least one of the phenylrings.

2. Background of the Invention

The curing of monomeric materials to produce polymeric thermoset resinsis well known in the art. In general, the curable monomers have one andcustomarily more than one active group which serves as a reactive sitefor the curing or crosslinking polymerization to produce a crosslinkedpolymer. However, for efficient curing of many or most polymerizablemonomers to produce crosslinked resins, for example the curing of anepoxy resin, the presence of a curing agent, catalytic or stoichimetric,is required to cause the curing or crosslinking to occur at anacceptable rate. Even in the presence of most curing agents the rate ofcuring is undesirably slow and the addition of an accelerator isrequired to obtain sufficiently rapid curing. Certain polymerizablemonomers do cure in the absence of added curing agent or accelerator butonly upon the application of high intensity energy, e.g., ultraviolet(UV) light.

There are, however, other monomeric materials which contain one or moreactive sites such that curing will take place upon application of heat.One class of such crosslinked resin precursor includes within themolecular structure one or more moieties of an arylcyclobutene,particularly a benzocyclobutene. Without wishing to be bound by anyparticular theory, it appears likely that upon application of heat thecyclobutene moieties undergo ring-opening to produce reactiveintermediates which react with active portions of adjacent molecules.The resulting resin have properties of rigidity and resistance to manycommon solvents.

A series of U.S. patents to Kirchhoff, of which U.S. Pat. No. 4,540,763is illustrative, describes the production and curing of a large numberof benzocyclobutene derivatives including multi-cyclic aromaticcompounds in which the aromatic rings are directly connected, orconnected by a functional group, to a carbon atom of the six-memberedring of a benzocyclobutene moiety. These derivatives are said to beself-curing. It would be of advantage, however, to provide a novel classof self-curing benzocyclobutene-type compounds of a different molecularstructure.

SUMMARY OF THE INVENTION

This invention provides novel cured products produced fromarylcyclobutene derivaties of di(hydroxyphenyl) compounds. Moreparticularly, the invention relates to cured products obtained bysubjecting arylcyclobutenealkylated di(hydroxyphenyl) compounds to theinfluence of heat.

DESCRIPTION OF THE INVENTION

The cured compositions of the invention are produced fromdi(hydroxyphenyl) compounds of up to two aromatic rings having on atleast one of the aromatic rings an arylcyclobutene-containingsubstituent where the phenyl group of the di(hydroxyphenyl) compound isconnected to a ring carbon of an aromatic 6-membered ring of anarylcyclobutene moiety by an alkylene linking group. These precursorsare produced by reaction of a di(hydroxyphenyl) compound with anarylcyclobutenealkyl compound. The compositions of the invention arerigid polymers produced at elevated temperature.

The di(hydroxyphenyl) compounds which are suitably employed asprecursors of the compositions of the invention have up to 30 carbonatoms and from 1 to 2 aromatic rings, inclusive. When two aromatic ringsare present, the rings are fused or are connected by a direct valencebond, alkylene of up to 8 carbon atoms, inclusive, oxy, thio, carbonyl,carboxyl, carbonato or sulfonyl. One class of such di(hydroxyphenyl)compounds is represented by the formula

    HO--X--OH                                                  (I)

wherein X is aromatic having up to 30 carbon atoms and from 1 to 2aromatic rings which, when two rings are present are fused or joined asdescribed above and have at least one hydroxyl substituent on eacharomatic ring. The moiety X in formula I is otherwise hydrocarbylcontaining only atoms of carbon and hydrogen besides any additionalatoms present in divalent linking groups or is substituted hydrocarbylcontaining additional atoms present as unreactive carbon atomsubstituents, e.g., halogens, preferably the middle halogens chloro orbromo. Illustrative di(hydroxyphenyl) compounds of formula I includehydroquinone, resorcinol, 1,5-dihydroxynaphthalene,4,4'-dihydroxy-2,2'-dimethylbiphenyl, 2,2-di(4-hydroxyphenyl)-propane,di(4-hydroxyphenyl)methane,2,2-bis(4-hydroxy-3,5-dibromophenyl)-propane, di(3-hydroxyphenyl) ether,di(4-hydroxy-3-ethylphenyl) ketone or di(4-hydroxyphenyl) carbonate.

A preferred class of di(hydroxyphenyl) compounds is represented by theformula ##STR1## wherein Alk is alkylene of up to 8 carbon atoms, Zindependently is alkyl, preferably lower alkyl of up to 4 carbon atomsinclusive, or halo, preferably middle halo, and z independently is aninteger from 0 to 3 inclusive, preferably 0 to 2. Thesedi(hydroxyphenyl) compounds are illustrated bydi(3-hydroxyphenyl)methane, 1,1-di(4-hydroxy-3-methylphenyl)-ethane,2,2-di(4-hydroxyphenyl)propane, 4,4-di(4-hydroxy-3-chlorophenyl)-octane,2,2-bis(4-hydroxy-3,5-dibromophenyl)propane and2-(3-hydroxyphenyl)-2-(2-hydroxyphenyl)propane. The preferred hydroxylsubstitution is para to the carbon atom connected to the Alk group and zis most preferably zero. The compound 2,2-di(4-hydroxyphenyl)propane,also known as bisphenol A or BPA, is a particularly preferreddi(hydroxyphenyl) compound. The di(hydroxyphenyl) compounds are knowncompounds or are produced by known methods.

To produce the ring-alkylated di(hydroxyphenyl) compounds, thedi(hydroxyphenyl) compounds are reacted with an arylcyclobutenealkylcompound represented by the formula

    Ar--R--W                                                   (II)

wherein Ar is an arylcyclobutene group, R is alkylene of up to 4 carbonatoms inclusive and W is an electron-withdrawing group.

Suitable W groups in the above formula II are those which when attachedto an aromatic ring are thought to be ring-deactivating andmeta-directing, or, expressed differently, are those groups commonlyreferred to as good "leaving groups" in nucleophillic substitutionreactions. Preferred W groups are upper halo, i.e., halogens other thanfluoro (chloro, bromo or iodo), or sulfonic ester such as aryl sulfate,e.g., tosylate, brosylate or nosylate, alkyl sulfonate, e.g., mesylateand fluoroalkyl sulfonate, for example triflate or nonaflate. The term Rof formula II is alkylene of up to 4 carbon atoms, e.g., methylene,1,2-ethylene or 1,4-butylene, but preferably is methylene.

The arylcyclobutene group Ar is an aromatic ring system of up to 4aromatic rings and up to 30 carbon atoms, inclusive, which contains atleast one cyclobutene ring fused to an aromatic ring. Suitable aromaticring systems are illustrated by the single aromatic ring system compoundbenzene, the fused aromatic ring system compounds naphthalene,anthracene and phenanthrene, the directly joined aromatic ring systemcompounds of two or more aromatic rings joined by an alkylene group ofup to 8 carbon atoms inclusive, e.g., diphenylalkanes such asdiphenylmethane and 2,2-diphenylpropane. The preferred aromatic ringsystem is the single ring system compound benzene and the preferredarylcyclobutene moiety is a benzocyclobutene moiety. The Ar group ishydrocarbyl containing only atoms carbon and hydrogen or is substitutedhydrocarbyl containing additional atoms as inert carbon atomsubstituents, e.g., cyano or middle halo. The preferred Ar group is abenzocyclobutene group.

In a particularly preferred embodiment of the invention, thearylcyclobutenealkyl compound is a halomethylcyclobutene of the formula##STR2## wherein W' is upper halo, i.e., chloro, bromo or iodo, butpreferably is chloro or bromo, especially chloro. Thehalomethylcyclobutenes are prepared by one of several reaction schemesdepending upon the desired spatial arrangement of the halomethylsubstituent and the cyclobutene ring. A 4-halomethylbenzocyclobutene isprepared from p-methylbenzyl halide, preferably p-methylbenzyl chloride,in two steps according to the procedure of Ewing et al, J. Chem. Soc.Chem. Comm., 1979, 207. Preparation of 3-chloromethylbenzocyclobutene iseffected by a similar procedure starting with o-methylbenzyl chloride.In this case, however, the procedure yields about 1:2 molar mixture of3-chloromethylbenzocyclobutene and 4-chloromethylbenzocyclobutene. Thismixture is separated into its individual components by conventionalmethods such as distillation or chromatographic separation oralternatively is used as such without separation of the isomers. Otherarylcyclobutenealkyl compounds are also known compounds or are producedby known methods.

The di(hydroxyphenyl) compound and the arylcyclobutenealkyl compound arereacted in the liquid phase in the presence of what is commonly referredto as a Friedel Crafts alkylation catalyst. Such catalysts includeacidic metal halides such as aluminum trichloride, boron trifluoride,zinc chloride, stannic chloride and ferric chloride, proton-containingacids such as sulfuric acid, hydrofluoric acid and phosphoric acid,acidic metal oxides such as silica and ferric oxide, and cationicexchange resins such as the class of sulfonated styrenedivinylbenzenecrosslinked resins marketed under the trademarks DOWEX™ Resin andAMBERLITE™ Resin. The alkylation catalyst is employed in a catalyticquantity. Amounts of alkylation catalyst from about 1% to about 5% byweight, based on total reactants, are satisfactory, although higher orlower amounts may also be used. The alkylation reaction is conducted ina liquid phase in an inert reaction diluent. Suitable reaction diluentsare liquid under reaction conditions and are capable of dissolving atleast a portion of each reactant at reaction temperature. Illustrativeof suitable reaction diluents are hydrocarbons or halohydrocarbons of upto 12 carbon atoms inclusive, including heptane, isooctane and dodecaneas well as ethylene dichloride, carbon tetrachloride, perfluorobutaneand perchloropropane. The preferred diluents are 1,2-dichloroethane andchloroform, especially 1,2-dichloroethane.

The alkylation reaction is conducted by contacting the di(hydroxyphenyl)compound, the arylcyclobutenealkyl compound and the catalyst in thereaction diluent and maintaining the mixture under alkylationconditions, while reactant/catalyst contact is maintained throughconventional methods such as shaking, stirring or refluxing. The ratioof di(hydroxyphenyl) compound to arylcyclobutenealkyl compound is notcritical although the ratio will influence the number of arylcyclobutenemoieties introduced onto each di(hydroxyphenyl) compound molecule. Ingeneral, molar ratios of the di(hydroxyphenyl) compound to thearylcyclobutenealkyl compound from about 8:1 to about 1:8 aresatisfactory although molar ratios from about 4:1 to about 1:1 arepreferred.

Suitable reaction temperatures are from about 20° C. to about 180° C.with reaction temperatures in the range from about 30° C. to about 150°C. being preferred. Good results are often obtained at the refluxtemperature of the reaction mixture under ambient temperature. Thereaction pressures that are suitable are those pressures which willmaintain the reaction mixture in a liquid phase at reaction temperature.Such pressures are typically up to about 20 atmospheres but more oftenare from about 0.8 atmospheres but more often are from about 0.8atmosphere to about 10 atmospheres. Subsequent to reaction thering-alkylated di(hydroxyphenyl) product is recovered by conventionalmethods such as diluent removal or filtration following precipitation ofthe product with a non-soluent.

The ring alkylated di(hydroxyphenyl) compounds which cure into thecompositions of the invention are characterized by the presence as asubstituent on at least one phenyl ring of the di(hydroxyphenyl)compound of a --R--Ar group wherein Ar and R have the previously statedmeanings. Some of the di(hydroxyphenyl) compounds will have more thanone Ar--R-- group within the molecule and some many have more than oneAr--R-- group on the same phenyl ring. The location and number ofAr--R-- groups is not critical, although the number of such groups willin part control the degree of crosslinking which will occur when thering-alkylated product is cured. In terms of the reactants as describedabove (formula I and formula II), the products are illustrated by theformula ##STR3## wherein Ar, R and X have the previously stated meaningsand r is an integer from 1 to 4 inclusive, preferably from 1 to 2inclusive. In terms of the preferred reactants of formulas Ia and IIathe preferred ring-alkylated products are represented by the formula##STR4## wherein Alk, Z, z and Ar have the previously stated meaningsand s independently is an integer from 0 to 2, preferably 0 to 1,inclusive with the proviso that at least one s is at least 1.

The nomenclature of the ring-alkylated products is somewhat difficultbecause of the complexity thereof, but representative products includedi(4-benzocyclobutenylmethyl)-2,2-di(4-hydroxyphenyl)propaneillustratively produced from 4-chloromethylbenzocyclobutene and2,2-di(4-hydroxyphenyl)propane andtri(3-benzocyclobutenylmethyl)-1,5-dihydroxynaphthalene illustrativelyproduced from 3-bromomethylbenzocyclobutene and1,5-dihydroxynaphthalene. Other products will be apparent fromconsideration of the above formulas for the reactants and the product.

The arylcyclobutenealkylated di(hydroxyphenyl) compound products aregenerally viscous oils or low-melting solids, the properties of whichdepend in part on the number of arylcyclobutenealkyl moieties permolecule. Products having a single arylcyclobutenealkyl moiety permolecule do not extensively cure or crosslink but will provide, uponheating, a rigid, at least relatively insoluble product.Arylcyclobutenealkylated di(hydroxyphenyl) compound products having twoor more alkylcyclobutenealkyl moieties will extensively cure orcrosslink to provide a product more clearly of the type termed thermosetresin. In either case, the curing of the products of the invention iseffected by the application of elevated temperature. Typically theproducts are heated to a temperature up to about 300° C. but more oftento a temperature of at least about 200° C. The resulting rigid,relatively insoluble products exhibit at least some degree ofself-polymerization and in some cases a considerable degree ofpolymerization. Alternatively, the ring-alkylated di(hydroxyphenyl)compounds serve to crosslink polymeric materials of a variety of typesincluding those having carbon-carbon unsaturation within the polymericmolecule such as polybutadiene, polyisoprene and styrene-butadienerubber. In yet another modification, the ring-alkylateddi(hydroxyphenyl) compound is substituted for a portion of the BPAemployed in the conventional production of thermoplastic resins, e.g.,arylate resins, and the resulting polymeric material will exhibit somedegree of self-curing. The rigid, insoluble products obtained by heatingthe arylcyclobutenealkylated di(hydroxyphenyl) compounds are processedby methods conventional for thermoset-type resins. Such resins findutility in applications where conventional thermoset resins areemployed, e.g., coatings and structural materials such as the aerospaceand electronic industries.

The invention is further illustrated by the following IllustrativeEmbodiments which should not be construed as limiting the invention.

ILLUSTRATIVE EMBODIMENT I

To a solution of 18.3 g (80 mmol) of 2,2-di(4-hydroxyphenyl)-propane in400 ml of 1,2-dichloroethane at 60° C. was added 6.1 g (40 mmol) of4-chloromethylbenzocyclobutene and 0.4 g of zinc chloride. The resultingmixture was heated at reflux for 3 hours and then cooled to ambienttemperature. The mixture was then washed with dilute hydrochloric acidand then with water, dried over magnesium sulfate and decolorized withcharcoal. Removal of the diluent under reduced pressure afforded aviscous amber oil. This crude product was chromatographed through asilica gel column using chloroform as an element. The first 500 ml ofeluent from the column was concentrated under reduced pressure to give12.1 g of a glassy solid. The proton NMR spectra of the product wereconsistent with a mixture of benzocyclobutenemethylated2,2-di(4-hydroxyphenyl)propane with an average substitution of 1.1benzocyclobutenemethyl moieties per molecule of2,2-di(4-hydroxyphenyl)propane.

ILLUSTRATIVE EMBODIMENT II

A mixture of 0.86 g (approx. 2.5 mmol) of the product of IllustrativeEmbodiment I and 10.84 g (47.5 mmol) 2,2-di(4-hydroxyphenyl)-propane wasadded to a mixture of 4.5 g sodium hydroxide, 3.0 g lauryl sulfate, 50ml 1,2-dichloroethane and 300 ml of water. The mixture was placed in aWaring blender and cooled to 0° C. A solution of isophthaloyl chloride(5.08 g, 25 mmol) and terephthaloyl chloride (5.08 g, 25 mmol) in 100 mlof 1,2-dichloroethane was added to the mixture in the blender at slowstirring speed. After the mixture was stirred for an additional 10minutes at high speed it was poured into 350 ml of acetone and theprecipitate was recovered by vacuum filtration. The precipitated polymerwas washed with 500 ml of water in a Waring blender, filtered, washed inthe funnel five times with 100 ml portions of water and dried at 50° C.in vacuo. Sixteen grams of an off-white powder were obtained. Protonnuclear magnetic resonance analysis indicated that the polymer hadapproximately 2.6% of the repeating units derived from thebenzocyclobutenemethylated product of Illustrative Embodiment I.Compression molding of this polymeric product for 10 minutes at 250° C.yielded a crosslinked film having a glass transition temperature of 191°C. which did not dissolve in 1,2-dichlroethane.

A control sample without benzocyclobutene moieties was prepared by thissame procedure by substituting the product of Illustrative Embodiment Iwith 2,2-di(4-hydroxyphenyl)propane. Compression molding at 250° C. for15 minutes gave a film which was soluble in 1,2-dichloroethane and had aglass transition temperature of 178° C.

ILLUSTRATIVE EMBODIMENT III

When a sample of the benzocyclobutenemethylated2,2-di(4-hydroxyphenyl)propane of Illustrative Embodiment I is heated ina mold at a temperature over 200° C., a rigid product will be obtainedwhich is only moderately soluble in 1,2-dichloroethane.

What is claimed is:
 1. A relatively insoluble, rigid polymer obtained byheating to a temperature up to about 300° C. aring-arylcyclobutenealkylated di(hydroxyphenyl) compound having at leastone arylcyclobutenealkyl substituent on at least one of the phenyl ringsin which the alkyl moiety of each arylcyclobutenealkyl group is attachedto a carbon atom of a six-membered aromatic ring.
 2. The rigid polymerof claim 1 obtained by heating to a temperature of at least about 200°C. the compound of the formula ##STR5## wherein Alk is alkylene of up to8 carbon atoms inclusive, Z is alkyl or halo, z is an integer from 0 to3 inclusive and s is an integer from 0 to 2 inclusive with the provisothat at least one s is at least
 1. 3. The rigid polymer of claim 2wherein Alk is 2,2-propylene.
 4. The rigid polymer of claim 3 wherein Zis halo.
 5. The rigid polymer of claim 4 wherein Z is bromo.
 6. Therigid polymer of claim 5 wherein z is zero.
 7. The rigid polymer ofclaim 6 wherein s is an integer from 0 to 1 inclusive.
 8. The rigidpolymer of claim 2 wherein Alk is methylene.
 9. The rigid polymer ofclaim 8 wherein Z is halo.
 10. The rigid polymer of claim 9 wherein Z isbromo.
 11. The rigid polymer of claim 9 wherein z is zero.
 12. The rigidpolymer of claim 10 wherein s is an integer from 0 to 1 inclusive.